CX500 SPA problem

Hello!

Sorry for my english...

I have CX500 with two SP: SP A and SP B.

I think the SP A is not working properly.

When I remove SP A  from CX500 or installed both SP - it's work fine. (see below)

When I remove SP B  from CX500 - it's don't work. And connected hosts dont see mapped LUNs.

That's what I see:

The SP’s power LED is steady green, and no amber LEDs is blinking on both SP.

Please help understand because of what is happening.

Thanks!